Heat sink including a heat dissipating fin and method for fixing the heat dissipating fin

ABSTRACT

A heat sink including a heat dissipating fin comprises (1) a heat dissipating fin having a plurality of mountain-shaped portions and base portions supporting the mountain-shaped portions, (2) a base member having a plurality of slits into which the mountain-shaped portions of the heat dissipating fin are to be inserted and a plurality of holes for fixing the heat dissipating fin, and (3) a fitting member, provided with a plurality of projecting portions corresponding to the plurality of holes of the base member, for fixing the heat dissipating fin between the base member and the fitting member itself.

RELATED APPLICATIONS

This application is a continuation-in-pan of, and incorporates byreference in its entirety, co-pending U.S. patent application entitled“HEAT SINK INCLUDING A HEAT DISSIPATING FIN AMD METHOD FOR FIXING THEHEAT DISSIPATING FIN”, having application No. 09/642,742, filed on Aug.18, 2000 (which issued as U.S. Pat. No. 6,357,514 on Mar. 19, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat sink including a heatdissipating fin and a method for fixing the heat dissipating fin to theheat sink main body. A heat sink including a heat dissipating finaccording to the present invention may be utilized not only for heatdissipating and cooling of a heat generating electronic component or thelike used in an electronic device but also for heat dissipating andcooling of articles in any field which require heat dissipation.

2. Related Art

A semiconductor chip or the like used in various electronic devices suchas a personal computer, a game console, an audio system or the like hasbeen made smaller in size, and larger in integration density toremarkably improve processing speed, and therewith heat generatingdensity thereof becomes much larger.

Various corrugated fins such as those comprising sequentially connectedelongate U shaped parts (hereinafter referred to as “elongated foldedfin”) are widely used as a means for dissipating the heat generated by asemiconductor chip or the like having large heat generating densitywhich is mounted in such electronic devices as a personal computer, agame console, an audio system or the like. Although the elongated foldedfin is light in weight and has a limited enveloped volume, the heatdissipating area thereof can be made wider.

The heat generated by a heat source is transferred to a heat transferplate, block or the like, and then the heat thus transferred isdissipated through the elongated folded fin attached to the heattransfer plate, block or the like. The elongated folded fin is joined tothe heat transfer plate, block or the like by brazing or soldering.Alternatively, the elongated folded fin is fixed to the heat transferplate, block or the like by caulking or screwing. Furthermore, theelongated folded fin is adhered by an adhesive agent, a double-sidedadhesive tape or the like.

However, the above-mentioned conventional method for attaching theelongated folded fin to the heat transfer plate, block or the like hasthe following problems. Namely, the method of joining the elongatedfolded fin to the heat transfer plate, block or the like by brazing orsoldering, as well as the method of adhering the heat transfer plate,block or the like by the adhesive agent have a problem of its highprocessing cost. Additionally, the method of joining the elongatedfolded fin to the heat transfer plate, block or the like by brazing orsoldering has a problem that the fin is softened and the strengththereof is lowered by the heat in the joining process.

The method of fixing the elongated folded fin to the heat transferplate, block or the like by caulking or screwing, as well as the methodof adhering the elongated folded fin to the heat transfer plate, blockor the like by the double-sided adhesive tape have a problem in whichthe heat transfer resistance (i.e, contact heat resistance) between theelongated folded fin and the heat transfer plate, block or the likebecomes large.

Furthermore, the method of adhering the elongated folded fin to the heattransfer plate, block or the like by an adhesive agent has a problem inwhich the products thus processed do not have uniform heat transferresistance, thus having a different quality in heat transfer resistance.

An object of the present invention is therefore to provide a heat sinkincluding a heat dissipating fin which is inexpensive in processingcost, uniform in heat transfer resistance and excellent in heat transferefficiency without degrading the strength of the fin, and a method forfixing the heat dissipating fin to the heat sink main body.

SUMMARY OF THE INVENTION

The inventors have been studying hard to solve the above-mentionedproblems in the conventional art. As a result, the following findingsare obtained.

More specifically, it has been found that it is possible to provide aheat sink including a heat dissipating fin, being inexpensive inprocessing cost, uniform in heat transfer resistance and excellent inheat transfer efficiency without degrading the strength of the fin, byfirstly preparing a heat dissipating fin in a shape of a folded fincomprising mountain-shaped portions, a base member and a fitting member,then forming in the base member square slits having the size and numbercorresponding to the width, depth, mountain pitch, number of mountainsof the heat dissipating fin, and holes for fixing the heat dissipatingfin, then making on the fitting member projecting portions correspondingto the holes, then inserting the heat dissipating fins into the slits,fitting the projecting portions into the holes, pressing the heatdissipating fin between the base member and the fitting member, andcaulking the heads of the fitted projecting portions, thereby fixing theheat dissipating fin.

Furthermore, it has been found that the same effect as described abovecan be also obtained by providing in a fitting member holes for fixing aheat dissipating fin and providing in a base member projecting portionscorresponding to the holes.

In addition, it has been found that it is possible to more effectivelyfix a heat dissipating fin between a base member and a fitting member byproviding a curved portion in a part of the base member and pressing theheat dissipating fin by the curved portion.

The present invention has been made on the basis of the informationobtained as described above.

The first embodiment of a heat sink of the present invention is a heatsink including a heat dissipating fin, comprising:

(1) a heat dissipating fin having a plurality of mountain-shapedportions and base portions supporting said mountain-shaped portions;

(2) a base member having a plurality of slits into which saidmountain-shaped portions of said heat dissipating fin are to be insertedand a plurality of holes for fixing said heat dissipating fin; and

(3) a fitting member, provided with a plurality of projecting portionscorresponding to said plurality of holes of said base member, for fixingsaid heat dissipating fin between said base member and the fittingmember itself.

The second embodiment of a heat sink of the present invention is a heatsink including a heat dissipating fin, comprising:

(1) a heat dissipating fin having a plurality of mountain-shapedportions and base portions supporting said mountain-shaped portions;

(2) a base member having a plurality of slits into which saidmountain-shaped portions of said heat dissipating fin are to be insertedand a plurality of projecting portions for fixing said heat dissipatingfin; and

(3) a fitting member, provided with a plurality of holes correspondingto said plurality of projecting portions of said base member, for fixingsaid heat dissipating fin between said base member and the fittingmember itself.

The third embodiment of a heat sink of the present invention is a heatsink including a heat dissipating fin, wherein:

said mountain-shaped portions of said heat dissipating fin are insertedinto said slits of said base member, said base portions of said heatdissipating fin are put between said base member and said fittingmember, said projecting portions are fitted into said holes, and saidprojecting portions are caulked, thereby said heat dissipating fin isfixed between said base member and said fitting member.

The fourth embodiment of a heat sink of the present invention is a heatsink including a heat dissipating fin, wherein:

at least a part of regions positioned between said plurality of slits ofsaid base member, said regions being to come into contact with said baseportions of said heat dissipating fin, forms a curved portion by beingdrawn down toward said fitting member in such manner that said heatdissipating fin is fixed between said base member and said fittingmember by means of an elastic action of said curved portion.

The fifth embodiment of a heat sink of the present invention is a heatsink including a heat dissipating fin, wherein:

when said heat dissipating fin is fixed between said base member andsaid fitting member in such manner that regions of said base memberwhich come into contact with said base portions of said heat dissipatingfin are drawn up by a distance corresponding to a thickness of said basemember toward said heat dissipating fin, a lower face of the baseportions of said heat dissipating fin and a lower face of said basemember are positioned nearly in a same plane.

The sixth embodiment of a heat sink of the present invention is a heatsink including a heat dissipating fin, wherein:

a heat pipe is thermally connected to said fitting member in such mannerthat heat transferred by said heat pipe is dissipated through saidfitting member and said heat dissipating fin.

The first embodiment of a method of the invention is a method for fixinga heat dissipating fin, comprising the steps of:

(1) preparing a heat dissipating fin comprising a plurality ofmountain-shaped portions and base portions supporting saidmountain-shaped portions;

(2) preparing a base member having a plurality of slits into which saidplurality of mountain-shaped portions are to be inserted and a pluralityof holes;

(3) preparing a fitting member provided with a plurality of projectingportions corresponding to said plurality of holes of said base member;

(4) inserting said mountain-shaped portions of said heat dissipating fininto said slits of said base member, putting said base portion of saidheat dissipating fin between said base member and said fitting member,and fitting said projecting portions into said holes; and

(5) caulking said projecting portions which are fitted into said holes,thereby fixing said heat dissipating fin between said base member andsaid fitting member.

The second embodiment of a method of the invention is a method forfixing a heat dissipating fin, comprising the steps of:

(1) preparing a heat dissipating fin comprising a plurality ofmountain-shaped portions and base portions supporting saidmountain-shaped portions;

(2) preparing a base member having a plurality of slits into which saidplurality of mountain-shaped portions are to be inserted and a pluralityof projecting portions;

(3) preparing a fitting member provided with a plurality of holescorresponding to said plurality of projecting portions of said basemember;

(4) inserting said mountain-shaped portions of said heat dissipating fininto said slits of said base member, putting said base portion of saidheat dissipating fin between said base member and said fitting memberand fitting said projecting portions into said holes; and

(5) caulking said projecting portions which are fitted into said holes,thereby fixing said heat dissipating fin between said base member andsaid fitting member.

The third embodiment of a method of the invention is a method for fixinga beat dissipating fin, further comprising the steps of:

in preparation of said base member, forming a curved portion by drawingdown at least a part of regions positioned between said plurality ofslits of said base member, said regions being to come into contact withsaid base portions of said heat dissipating fin, toward said fittingmember in such manner that said heat dissipating fin is fixed betweensaid base member and said fitting member by means of an elastic actionof said curved portion.

The fourth embodiment of a method of the invention is a method forfixing a heat dissipating fin, further comprising the steps of:

in preparation of said base member, when fixing said heat dissipatingfin between said base member and said fitting member in such manner thatregions of said base member which come into contact with said baseportions of said heat dissipating fin are drawn up by a distancecorresponding to a thickness of said base member toward said heatdissipating fin, a lower face of the base portion of said heatdissipating fin and a lower face of said base member are prepared so asto be positioned nearly in the same plane.

The fifth embodiment of a method of the invention is a method for fixinga heat dissipating fin, further comprising the step of providing a heatpipe so as to be thermally connected to said fitting member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view showing a heat sink including aheat dissipating fin of the present invention.

FIG. 2 is a partial cross-sectional view showing a heat sink including aheat dissipating fin of the present invention.

FIG. 3 is a partial longitudinal-sectional view showing a heat sinkincluding a heat dissipating fin of the present invention.

FIG. 4 shows essential elements of a heat sink including a heatdissipating fin of the present invention.

FIG. 5 is a partial cross-sectional view showing a heat sink including aheat dissipating fin of the present invention provided with a heat pipe.

FIG. 6 is a partial longitudinal-sectional view showing a heat sinkincluding a heat dissipating fin of the present invention provided witha heat pipe.

FIG. 7 is a perspective view showing an embodiment of a base member in aheat sink including a heat dissipating fin of the present invention.

FIG. 8 is a partial cross-sectional view showing an embodiment of a heatsink including a heat dissipating fin of the present invention.

FIG. 9 is a schematic perspective view showing other embodiment of aheat sink including a heat dissipating fin of the present invention.

FIG. 10 shows essential elements of other embodiment of a heat sinkincluding a heat dissipating fin of the present invention.

FIG. 11 is a partial cross-sectional view showing other embodiment of aheat sink including a heat dissipating fin of the present invention.

FIG. 12 is a partial cross-sectional view along A—A line in FIG. 11showing the embodiment of a heat sink including a heat dissipating finof the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A heat sink including a heat dissipating fin of the present invention isdescribed with reference to the drawings.

A heat sink including a heat dissipating fin of the invention comprises:

(1) a heat dissipating fin having a plurality of mountain-shapedportions and base portions supporting said mountain-shaped portions;

(2) a base member having a plurality of slits into which saidmountain-shaped portions of said heat dissipating fin are to be insertedand a plurality of holes for fixing said heat dissipating fin; and

(3) a fitting member, provided with a plurality of projecting portionscorresponding to said plurality of holes of said base member, for fixingsaid heat dissipating fin between said base member and the fittingmember itself.

More specifically, in the above-mentioned embodiment, the base member isprovided with slits and holes, and the fitting member is provided withprojecting portions corresponding to the holes.

FIG. 4 shows essential elements of a heat sink including a heatdissipating fin of the present invention. As shown in FIG. 4, a heatdissipating fin 2 comprises a plurality of mountain-shaped portions 21and base portions 22 supporting the mountain-shaped portions. A basemember 1 has a plurality of slits 12 and a plurality of holes 10 formedtherein. A fitting member 3 has projecting portions 4 thereoncorresponding to the holes 10.

FIG. 1 is a schematic perspective view showing a heat sink including aheat dissipating fin of the present invention. In FIG. 1, themountain-shaped portions 21 of the heat dissipating fin 2 described inFIG. 4 are inserted into the slits 12 to project upward above the basemember 1, and the projecting portions 4 are fitted into the holes 10 andtheir heads are caulked. As shown in FIG. 1, the heat dissipating fin 2is sandwiched and fixed between the base member and the fitting member.In this situation, since the lower face of the regions 13 positionedbetween the slits and the upper face of the base portions 22 of the heatdissipating fin are fast pressed and fixed to each other, the contactheat resistance therebetween can be made small.

In addition, since the lower face of the base portions 22 of the heatdissipating fin and the upper face of the fitting member 3 are fastpressed and fixed to each other in the same way, the contact heatresistance therebetween can be made small. Therefore, heat isefficiently transferred from the fitting member directly to the heatdissipating fin, and furthermore, heat is efficiently transferred fromthe fitting member partially through the base member to the heatdissipating fin.

Furthermore, in a heat sink including a heat dissipating fin of thepresent invention, as described above, the mountain-shaped portions 21of the heat dissipating fin 2 are inserted into the slits 12 of the basemember 1. The base portions 22 of the heat dissipating fin 2 is putbetween the base member 1 and the fitting member 3. The projectingportions 4 are fitted into the holes 10, and the heads of the projectingportions 4 are caulked. Thus, the heat dissipating fin 2 is fixedbetween the base member 1 and the fitting member 3.

Furthermore, A heat sink including a heat dissipating fin comprises: (1)a heat dissipating fin having a plurality of mountain-shaped portionsand base portions supporting said mountain-shaped portions; (2) a basemember having a plurality of slits into which said mountain-shapedportions of said heat dissipating fin are to be inserted and a pluralityof projecting portions for fixing said heat dissipating fin; and (3) afitting member, provided with a plurality of holes corresponding to saidplurality of projecting portions of said base member, for fixing saidheat dissipating fin between said base member and the fitting memberitself.

More specifically, in the above-mentioned embodiment, the base member isprovided with slits and projecting portions and the fitting member isprovided with holes corresponding to the projecting portions.

FIG. 2 is a partial cross-sectional view showing a heat sink including aheat dissipating fin of the present invention.

As shown in FIG. 2, the base portions 22 of the heat dissipating fin 2is put and fixed between the base member 1 and the fitting member 3. Inthis situation, when a specific recessed portion is formed in advance inthe fitting member 3 so as to receive the base portion 22 of the heatdissipating fin 2 therein, the heat dissipating fin 2 can be fit withoutvacant space between the base member 1 and the fitting member 3.

Furthermore, as shown in FIG. 2, the projecting portions 4 provided onthe fitting member 3 are inserted into the holes 10 provided in the basemember 1 and the heads of the projecting portions 4 are caulked. A heatsink of the present invention in which a heat dissipating fin is put andfixed between the base member and the fitting member is fixed on acircuit board 5 by fitting the peripheral portion of the base member 1on the circuit board 5.

A heat generating element 6 is disposed at a specific location on thecircuit board, and the heat generating element 6 is connected to thefitting member 3 through a heat-conductive rubber sheet 7 in a statewhere there is no heat transfer resistance. Therefore, the heatgenerated by the heat generating element 6 is transferred to theheat-conductive rubber sheet 7, the fitting member 3 and the heatdissipating fin 2, and is dissipated into the atmosphere.

FIG. 3 is a partial longitudinal-sectional view showing a heat sinkincluding a heat dissipating fin of the present invention.

As shown in FIG. 3, the mountain-shaped portions 21 of the heatdissipating fin 2 are inserted into the slits 12 of the base member 1,and the base portions 22 of the heat dissipating fin 2 is placed betweenthe fitting member 3 and the regions 13 which are positioned between theslits of the base member 1. The projecting portions 4 are inserted intothe holes 10 of the base member 1 and the heads of the projectingportions are caulked, thus the heat dissipating fin 2 is fixed.

A heat generating element 6 is disposed at a specific location on thecircuit board, and the heat generating element 6 is connected to thefitting member 3 through a heat-conductive rubber sheet 7 in a statewhere there is no heat transfer resistance. Therefore, as described inFIG. 2, the heat generated by the heat generating element 6 istransferred to the heat-conductive rubber sheet 7, the fitting member 3,the base portions 22 and the mountain-shaped portions 21 of the heatdissipating fin 2, and is dissipated into the atmosphere.

Moreover, in a heat sink including a heat dissipating fin of the presentinvention, at least a part of regions positioned between a plurality ofslits of a base member, which regions are to come into contact with thebase portions of the heat dissipating fin, forms a curved portion bybeing drawn down toward the fitting member in such manner that the heatdissipating fin is fixed between the base member and the fitting memberby means of an elastic action of the curved portion.

The above-mentioned embodiment of a heat sink including a heatdissipating fin of the present invention is described more in detailwith reference to FIGS. 7 and 8.

FIG. 7 is a perspective view showing am embodiment of a base member in aheat sink including a heat dissipating fin of the present invention. Asshown in FIG. 7, a base member 1 is provided with a plurality of slits12 and holes 10, and curved portions 11 formed by being drawn downtoward a fitting member 3 are provided in regions 8 positioned betweenthe slits 12. The width and depth of the slits and the numbers thereofare formed so as to correspond to the width, depth, mountain pitch andnumber of the mountain-shaped portions of the heat dissipating fin used.

The shape of the curved portion 11 formed by being drawn down isdetermined in consideration of the material, thickness and the like ofthe base member. When the heat dissipating fin 2 is placed between thebase member 1 and the fitting member 3, since the curved portions 11formed by being drawn down as described above presses elastically thebase portions of the heat dissipating fin, the heat dissipating fin ismore effectively and securely fixed. The curved portion may be formed inthe form of a triangle and the number of the curved portions is notlimited to one.

FIG. 8 is a partial cross-sectional view showing an embodiment of a heatsink including a heat dissipating fin of the present invention. FIG. 8shows a state where the curved portion 11 formed by being drawn down asdescribed above presses elastically the base portion 22 of the heatdissipating fin 2. More specifically, mountain-shaped portions 21 of theheat dissipating fin 2 are inserted into the slits of the base memberand the base portions 22 of the heat dissipating fin 2 are elasticallypressed by the curved portions 11 formed in the regions 8 positionedbetween the slits of the base member. The projecting portions 4 of thefitting member 3 are inserted into the holes 10 provided in the basemember and the heads of the projecting portions are caulked. As aresult, the heat dissipating fin is effectively fixed between the basemember and the fitting member.

Furthermore, in a heat sink including a heat dissipating fin of thepresent invention, regions of a base member which come into contact withthe base portions of the heat dissipating fin are drawn up by a distancecorresponding to the thickness of the base member toward the heatdissipating fin, and then the heat dissipating fin is fixed between thebase member and the fitting member in such manner that the lower face ofthe base portions of the heat dissipating fin and the lower face of thebase member are positioned nearly in the same plane.

The above-mentioned embodiment of a heat sink including a heatdissipating fin of the present invention is described more in detailwith reference to FIGS. 5 and 6.

FIG. 5 is a partial cross-sectional view showing a heat sink including aheat dissipating fin of the present invention provided with a heat pipe.As shown in FIG. 5, portions including the regions positioned betweenslits of the base member 1 are drawn up by a distance corresponding tothe thickness of the base member 1 toward the mountain-shaped portions21 of the heat dissipating fin 2. When the base portions 22 of the heatdissipating fin 2 are placed and fixed between the base member 1 and thefitting member 3, the lower face of the base portions 22 of the heatdissipating fin 2 and the lower face of the base member 1 are positionednearly in the same plane.

FIG. 6 is a partial longitudinal-sectional view showing a heat sinkincluding a heat dissipating fin provided with a heat pipe of thepresent invention. As shown in FIG. 6, portions including the regions 8positioned between slits of the base member 1 are drawn up by a distancecorresponding to the thickness of the base member 1 toward themountain-shaped portions 21 of the heat dissipating fin 2. When the baseportions 22 of the heat dissipating fin 2 are placed and fixed betweenthe base member 1 and the fitting member 3, the lower face of the baseportions 22 of the heat dissipating fin 2 and the lower face of the basemember 1 are positioned nearly in the same plane. According to thisembodiment, the heat dissipating fin is effectively fixed between thebase member 1 and the fitting member 3.

Furthermore, in a heat sink including a heat dissipating fin of thepresent invention, a heat pipe is thermally connected to a fittingmember. An outline thereof is shown in FIGS. 5 and 6. In FIG. 5, a heatpipe is attached through a heat-conductive rubber sheet 7 to a heatgenerating element 6 positioned on a circuit board 5. The heat pipe 9 isextended toward the heat dissipating fin, is bent nearly at a rightangle and is arranged along the heat dissipating fin. Heat generated bythe heat generating element 6 is transferred by the heat pipe 9 to thelower part of the heat dissipating fin and then is dissipated by theheat dissipating fin into the atmosphere. The shape of the heat pipe isdetermined in such manner that the heat can be most efficientlytransferred depending upon the positions of the heat generating elementand the heat dissipating fin. FIG. 6 shows a longitudinal sectional viewof the heat sink including the heat pipe. As shown in FIG. 6, the heatpipe reaching to the lower part of the heat dissipating fin is bent andarranged in the longitudinal direction of the heat dissipating fin.

Next, a method for fixing a heat dissipating fin of the presentinvention to the heat sink body is described.

A method for fixing a heat dissipating fin of the present inventioncomprises the steps of:

(1) preparing a heat dissipating fin comprising a plurality ofmountain-shaped portions and base portions supporting saidmountain-shaped portions;

(2) preparing a base member having a plurality of slits into which saidplurality of mountain-shaped portions are to be inserted and a pluralityof holes;

(3) preparing a fitting member provided with a plurality of projectingportions corresponding to said plurality of holes of said base member;

(4) inserting said mountain-shaped portions of said heat dissipating fininto said slits of said base member, putting said base portion of saidheat dissipating fin between said base member and said fitting member,and fitting said projecting portions into said holes; and

(5) caulking said projecting portions which are fitted into said holes,thereby fixing said heat dissipating fin between said base member andsaid fitting member.

More specifically, in the above-mentioned method, the base member isprovided with slits and holes, and the fitting member is provided withprojecting portions corresponding to the holes.

Furthermore, a method for fixing a heat dissipating fin of the presentinvention comprises the steps of:

(1) preparing a heat dissipating fin comprising a plurality ofmountain-shaped portions and base portions supporting saidmountain-shaped portions;

(2) preparing a base member having a plurality of slits into which saidplurality of mountain-shaped portions are to be inserted and a pluralityof projecting portions;

(3) preparing a fitting member provided with a plurality of holescorresponding to said plurality of projecting portions of said basemember;

(4) inserting said mountain-shaped portions of said heat dissipating fininto said slits of said base member, putting said base portion of saidheat dissipating fin between said base member and said fitting memberand fitting said projecting portions into said holes; and

(5) caulking said projecting portions which are fitted into said holes,thereby fixing said heat dissipating fin between said base member andsaid fitting member.

More specifically, in the above-mentioned method, the base member isprovided with slits and projecting portions, and the fitting member isprovided with holes corresponding to the projecting portions.

Furthermore, the method for fixing a heat dissipating fin of the presentinvention further comprises the steps of: in preparation of the basemember, a curved portion is formed by drawing down at least a part ofregions positioned between the plurality of slits of the base member,which regions are to come into contact with the base portions of theheat dissipating fin, toward the fitting member in such manner that theheat dissipating fin is fixed between the base member and the fittingmember by means of an elastic action of the curved portion.

In addition, the method for fixing a heat dissipating fin of the presentinvention further comprises the steps of: in preparation of the basemember, when fixing the heat dissipating fin between the base member andthe fitting member in such manner that regions of the base member whichcome into contact with the base portions of the heat dissipating fin aredrawn up by a distance corresponding to a thickness of the base membertoward the heat dissipating fin, a lower face of the base portion of theheat dissipating fin and a lower face of the base member are prepared soas to be positioned nearly in the same plane.

Furthermore, the method for fixing a heat dissipating fin of the presentinvention further comprises the step of providing a heat pipe so as tobe thermally connected to the fitting member.

As described above, the positioning of the heat dissipating fin can beimplemented by forming slits in the base member which are formed inaccordance with the shape of mountain-shaped portions (the width, depth,mountain pitch and number of mountains) of the heat dissipating fin.Furthermore, the regions positioned between the slits which are residualarea of the base member function as pressing plates. In addition, thethree components which are the heat dissipating fin, the base member andthe fitting member are thermally connected to one another by pressingsandwich the heat dissipating fin between the fitting member and thebase member.

Furthermore, since the heads of the projecting portions are caulked in astate of being pressed down, the three components are kept in a state ofbeing thermally connected even if the pressing force is released.

FIG. 9 is a schematic perspective view showing other embodiment of aheat sink including a heat dissipating fin of the present invention.Other embodiment of a beat sink including a heat dissipating finthermally connected to a heat generating element through a heatconductive rubber sheet, comprises:

(1) a heat dissipating fin having a plurality of mountain-shapedportions and base portions supporting said mountain-shaped portions; and

(2) a base member having a plurality of slits into which saidmountain-shaped portions of said heat dissipating fin are to beinserted.

FIG. 10 shows essential elements of other embodiment of a heat sinkincluding a heat dissipating fin of the present invention. As shown inFIG. 10, a heat dissipating fin 2 comprises a plurality ofmountain-shaped portions 21 and base portions 22 supporting themountain-shaped portions. A hole portions 23 are provided on the baseportion 22 located on the respective ends portion thereof. A base member1 has a plurality of slits 12 and corresponding holes 10 formed thereinto the hole portions 23.

More specifically, in the above-mentioned embodiment, the fitting memberis not included. Accordingly, in the above-mentioned embodiment, themountain-shaped portions 21 of the heat dissipating fin are insertedinto the slits 12 of the base member 1, and the base portions 22 of theheat dissipating fin 2 are put between the base member 1 and a heatgenerating element 6 through a heat conductive rubber sheet 7, as shownin FIG. 11. In addition, a bolt 24 may be inserted into the hole portion23 and the hole 10, and a nut 25 is screwed on the end of the bolt,thus, the base portion 22 of the heat dissipating fin 2 is pressed tothe heat generating element 6 through the heat conductive rubber sheetby means of the bolt and nut which fixes the base member 1 and thecircuit board 5.

FIG. 12 is a partial cross-sectional view along A—A line in FIG. 11showing the embodiment of a heat sink including a heat dissipating finof the invention. As shown in FIG. 12, a plurality of heat generatingelements 6 are thermally connected to the base portions 22 of the heatdissipating fin 22 through the heat conductive rubber sheet 7.Preferably, the width of the heat dissipating fin 22 is the same as thesize (i.e., width) of the heat generating element 6, as shown in FIG.11. With the use of the bolt and nut, the heat generating element andthe base portion of the heat dissipating fin can be firmly fixed in asandwiched manner, thus reducing heat resistant therebetween.

Furthermore, in other embodiment of a heat sink including a heatdissipating fin, at least a part of regions positioned between theplurality of slits of the base member, the regions of which come intocontact with the base portions of the heat dissipating fin, forms acurved portion by being drawn down toward the heat generating element insuch manner that the heat dissipating fin is fixed between the basemember and the heat generating element through the heat conductiverubber sheet by means of an elastic action of the curved portion.

As shown in FIG. 7, a base member 1 is provided with a plurality ofslits 12 and holes 10, and curved portions 11 formed by being drawn downtoward a heat generating element (not shown) are provided in regions 8positioned between the slits 12. The width and depth of the slits andthe numbers thereof are formed so as to correspond to the width, depth,mountain pitch and number of the mountain-shaped portions of the heatdissipating fin used.

The shape of the curved portion 11 formed by being drawn down isdetermined in consideration of the material, thickness and the like ofthe base member. When the heat dissipating fin 2 is placed between thebase member 1 and the heat generating element through a heat conductiverubber sheet (not shown), since the curved portions 11 formed by beingdrawn down as described above presses elastically the base portions ofthe heat dissipating fin, the heat dissipating fin is more effectivelyand securely fixed. The curved portion may be formed in the form of atriangle and the number of the curved portions is not limited to one.

Furthermore, in other embodiment of a heat sink including a heatdissipating fin, a heat pipe may be further connected to the baseportions of the heat dissipating fin.

A heat sink including a heat dissipating fin of the present invention isdescribed more in detail by means of examples.

EXAMPLE Example 1

According to the present invention, a heat generating element (of 25 mmin length, 25 mm in width, 2 mm in height, and 15 W in heat generatingrate) mounted on a circuit board (of 150 mm in length, 70 mm in widthand 1.2 mm in thickness) of an electronic device was cooled by a heatsink including a heat dissipating fin comprising the following.

More specifically, as the base member in the heat sink, a shieldingplate for electromagnetic shield (of 150 mm in length, 70 mm in width,0.5 mm in thickness) which is made of aluminum A1050 was used.

As the heat dissipating fin, a folded (corrugated) fin made of aluminumA1050 in which the height of the mountain-shaped portions is 35 mm, thepitch of mountains is 4 mm, the depth is 20 mm, the number of mountainsis 8, and the thickness of the fin plate is 0.4 mm was used.

As the fitting member, a heat receiving and heat transfer block made byan aluminum die casting process (of 90 mm in length, 45 mm in width and4 mm in thickness) was used, and 15 pins each being 2 mm in outerdiameter and 1.2 mm in height were provided thereon as the projectingportions.

In the base member, 8 slits of 2.6 mm×20.2 mm in size for the heatdissipating fin were formed, and in addition, 15 holes of 2.2 mm indiameter into which the projecting portions are to be inserted wereformed.

The regions positioned between slits of the base member were uniformlydrawn up by 0.4 mm toward the mountain-shaped portions in such mannerthat the bottom face of the heat dissipating fin and the bottom face of(the main body of) the base member form the same plane, when themountain-shaped portions are inserted into the slits of the base memberand the heat dissipating fin is placed between, the base member and thefitting member.

A heat sink was prepared by inserting the mountain-shaped portions intothe slits from the lower side of the base member, pressing sandwich theheat dissipating fin between the base member and the fitting member bymeans of a press, and caulking the heads of the pins which are theprojecting portions.

Furthermore, a heat transfer rubber sheet (of 25 mm in length, 25 mm inwidth, 1 mm in thickness, and 2.5 W/mk in heat transfer rate) wasadhered onto the heat generating element.

The circuit board and the heat sink were screwed on each other, and thefitting member of the heat sink was attached at a position where theheat transfer rubber sheet became 0.8 mm in thickness.

In an apparatus including the heat sink thus formed, a ventilating fanis installed and a wind of 1.5 m/s in wind velocity flows through theheat dissipating fin.

The apparatus was operated for four hours, and the surface temperatureof the heat generating element was measured. As a result, a temperaturerise from the atmospheric temperature was 65° C. and the heat resistanceincluding the heat transfer rubber sheet was 4.3° C./W, thus showingexcellent performance.

Example 2

A heat sink including a heat dissipating fin was prepared by embedding aheat pipe of 3 mm in diameter and 90 mm in length in the fitting memberused in the Example 1.

More specifically, an L-shaped groove of 2.9 mm in width, 2.9 in depthand 90 mm in length was formed in the middle portion of the fittingmember, which was positioned 45 mm laterally from one end of the fittingmember. The L-shaped groove was formed therein along the longitudinaldirection of the heat dissipating fin.

The other components and a method for fabricating them were the same asthose shown in Example 1.

A wind inside the apparatus was also the same as described in Example 1.

The heat sink including the above-mentioned heat pipe were operated todissipate and cool the heat generated by the heat generating element,and the surface temperature of the heat generating element was measured.As a result, a temperature rise from the atmospheric temperature was 43°C. and the heat resistance including the heat transfer rubber sheet was2.8° C./W, thus showing remarkably excellent performance.

Example 3

According to the present invention, a heat generating element (of 25 mmin length, 25 mm in width, 2 mm in height, and 15 W in heat generatingrate) mounted on a circuit board (of 150 mm in length, 70 mm in widthand 1.2 mm in thickness) of an electronic device was cooled by a heatsink including a heat dissipating fin comprising the following.

More specifically, as the base member in the heat sink, a shieldingplate for electromagnetic shield (of 150 mm in length, 70 mm in width,0.5 mm in thickness) which is made of aluminum A1050 was used.

As the heat dissipating fin, a folded (corrugated) fin made of aluminumA1050 in which the height of the mountain-shaped portions is 35 mm, thepitch of mountains is 4 mm, the depth is 20 mm, the number of mountainsis 8, and the thickness of the fin plate is 0.4 mm was used.

As the fitting member, a heat receiving and heat transfer block made byan aluminum die casting process (of 90 mm in length, 45 mm in width and4 mm in thickness) was used, and 15 hole each being 2.2 mm in diameterinto which the projecting portion describe later are to be inserted wereformed. In the base member, 8 slits of 2.6 mm×20.2 mm in size for theheat dissipating fin were formed, and in addition, 15 pins each being 2mm in outer diameter and 1.2 mm in height for the projecting portionwere formed.

Furthermore, a curved portion of 15 mm in curvature radius was formed inthe middle portion of the region positioned between slits of the basemember in such manner that the respective curved portions formed in theregions positioned between the slits press elastically the base portionsof the heat dissipating fin when the mountain-shaped portions of theheat dissipating fin are inserted into the slits and the heal,dissipating fin is placed between the base member and the fittingmember.

The heat sink was prepared by inserting the mountain-shaped portionsinto the slits from the lower side of the base member, pressing sandwichthe heat dissipating fin between the base member and the fitting memberby means of a press, and caulking the heads of the pins which are theprojecting portions.

Furthermore, a heat transfer rubber sheet (of 25 mm in length, 25 mm inwidth, 1 mm in thickness, and 2.5 W/mk in heat transfer rate) wasadhered onto the heat generating element.

The circuit board and the heat sink were screwed on each other, and saidfitting member of the heat sink was attached at a position where theheat transfer rubber sheet became 0.8 mm in thickness.

In an apparatus including the heat sink thus formed, a ventilating fanis installed and a wind of 1.5 m/s in wind velocity flows through theheat dissipating fin.

The apparatus was operated for four hours, and the surface temperatureof the heat generating element was measured. As a result, a temperaturerise from the atmospheric temperature was 65° C. and the heat resistanceincluding the heat transfer rubber sheet was 4.3° C./W, thus showingexcellent performance.

According to the present invention, in case of providing slits in thebase member which is in accordance with the shape (the width, depth,mountain pitch and number of the mountains) of mountain-shaped portionsof the heat dissipating fin, the external shape of the base member isgenerally formed by means of a press. According to the presentinvention, therefore, since the external shape of the base member andthe slits can be formed at the same time, it is possible to prepare thebase member inexpensively and accurately on a mass-production basis.Furthermore, the mountain-shaped portions of the heat dissipating fincan be easily inserted into the slits by leaving some margin indimensions of the slits, while applying an insertion guiding jig.

In addition, according to the present invention, since the heatdissipating fin is pressed sandwich and fixed between the fitting memberand the base member, the three components of the heat dissipating fin,the fitting member and the base member are well thermally connected toone another and the heat transfer resistance is reduced. It is possibleto more effectively perform heat dissipation and cooling when a heatpipe is attached thereto.

Moreover, according to the present invention, since the heads of pins asthe projecting portions are caulked in a state where the heatdissipating fin is pressed between the fitting member and the basemember, the three components are kept in a state of being well thermallyconnected to one another even if the pressing, force is released.

Still further, since pressing and caulking are performed by a press, itis possible to inexpensively and accurately perform a mass production.

According to a heat sink of the present invention, therefore, it ispossible to inexpensively fix a heat dissipating fin with a low heattransfer resistance on a mass production basis.

According to the present invention, there can be provided a heat sinkincluding a heat dissipating fin, being inexpensive in processing cost,uniform in heat transfer resistance and excellent in heat efficiencywithout degrading the strength of the fin, and a method for fixing theheat dissipating fin to the heat sink main body.

What is claimed is:
 1. A heat sink including a heat dissipating finthermally connected to a heat generating element through a heatconductive rubber sheet, comprising: (1) a heat dissipating fin having aplurality of mountain-shaped portions and base portions supporting saidmountain-shaped portions; and (2) a base member having a plurality ofslits, wherein said mountain-shaped portions of said heat dissipatingfin are inserted into said slits of said base member, said base portionsof said heat dissipating fin are put between said base member and a heatgenerating element through a heat conductive rubber sheet.
 2. A heatsink including a heat dissipating fin as claimed in claim 1, wherein: atleast a part of regions positioned between said plurality of slits ofsaid base member, said regions being to come into contact with said baseportions of said heat dissipating fin, forms a curved portion by beingdrawn down toward said heat generating element in such manner that saidheat dissipating fin is fixed between said base member and said heatgenerating element through said heat conductive rubber sheet by means ofan elastic action of said curved portion.
 3. A heat sink including aheat dissipating fin as claimed in claim 2, which further includes atleast one bolt and nut, said bolt is inserted into a hole portionprovided on respective end portions of said base portions of said heatdissipating fin, and corresponding hole provided on said base member. 4.A heat sink including a heat dissipating fin as claimed in any one ofclaims 1 and 2, further comprising: a heat pipe connected to said baseportions of said heat dissipating fin.
 5. A heat sink including a heatdissipating fin as claimed in claim 3, wherein further comprising: aheat pipe connected to said base portions of said heat dissipating fin.